Nitrogen is an important plant nutrient. In addition to phosphorous, potassium, and other nutrients, nitrogen is needed to support the growth and development of plant life. Some plants, such as legumes, through a symbiotic relationship with Rhizobium bacteria, take up elemental nitrogen from the atmosphere and fix this nitrogen into the soil. However, most plants grown to produce human and animal food are not legumes and require the use of nitrogen fertilizer in order to sustain their agricultural production.
The most widely used and agriculturally important high-analysis nitrogen fertilizer is urea, CO(NH2)2. Most of the urea currently produced is used as a fertilizer in its granular or prilled form. The proposed invention is a fertilizer prepared by combining a solid, flowable urea formaldehyde polymer (UFP) with a urea source such as molten and granulating or prilling, or combining with a solid urea. The UFP may be used to replace an aqueous urea formaldehyde (UF) solution, such as UF 85, and provides the desired crush strength, low biuret content and/or storage and handling properties. The desired crush strength is greater than or equal to about 2.5 pounds. Biuret is an undesirable by-product of synthetic urea production that may be phytotoxic at higher concentrations. The UFP absorbs ammonia, which may prevent the undesirable formation of biuret. It is desirable to have less than about 1.75% biuret in the fertilizer composition.
Optionally, the solid UFP may be used in combination with an aqueous UF solution or mixture. Other synthetic urea products than fertilizer are also contemplated in this invention, including adhesives, livestock feed and industrial emissions control.
Granulated solid urea is hygroscopic, and tends to clump when stored under humid conditions. Absorbent materials, such as attapulgite clay and diatomaceous earth are blended with granulated urea to prevent clumping and aid in the storage and handling of solid urea. Blending UFP with solid urea, prevents clumping of the urea and aids in the storage and handling of the product.